Rotary pump



May 23, 1939. H A. CENTERVALL ROTARY PUMP Original Filed July 11, 1931 5 Sheets-Sheet 1 INVENTOR. 3

By al 9%] 17s ATTORNEYS,

y 23, 1939- H. A. CENTERVALL 2,159,005

ROTARY PUMP Original Filed July 11, 1931 .5 Sheets-Sheet 2 '12; ATTORNEYS,

y 1939- H. A. CENTERVALL ROTARY PUMP Original Filed July-ll, 1931 5 Sheets-Sheet 3 NmN NNx

May 23, 1939- H. A. CENTERVALL ROTARY PUMP 1931 5 Sheets-Sheet 4 Original Fil ed July 11,

May 23, 1939.

H A. CENTERVALL ROTARY PUMP Original Filed July 11, 1931 5 Sheets-Sheet 5 -i TrW/m 4 M 2 7 i W. 7 M 2 6 0 E 2 INVENTOR.

i ATTORNEYS,

Patented May 23, 1939 UNITED STATES ROTARY rum Hugo A. Centervall, Brooklyn, N. Y., assignor to Manly Corporation, New York, N. Y., a corporation 01' Delaware Original application July 11, 1931, Serial No.-

Divided and this application January 24, 1936, Serial No. 60,608

9 Claims. (Cl. 103-161) This invention relates to hydraulic mechanism for the transmission of power at variable speeds, and more especially to improvements in pumps and motors used with such transmission mechanism.

The use of hydraulic transmission devices. wherein use is made of 'a power driven pump for forcing a current of liquid into the cylinders of a motor operatively connected with the driving shaft of whatever mechanism is to be operated, control of the speed of the driven member being eflected by varying the pump stroke is becoming increasingly widespread.

Great difllculty has been encountered, however,

' in the operation of known hydraulic transmission devices due to overheating caused principally by friction of the parts and the frictional resistance oilfered to the flow of the liquid, generally oil, through the various channels, ports and valves. This heat, generated from these or any other causes, has resulted in serious impairment to the eflicienby of the devices, both because of the deteriorating eil'ect upon the oil and the changing of its viscosity and further because of theexpanslon oi the metal parts, which are neces sarily close fitting, causing binding of the parts, or leakage, or both. The amount oi such overheating is recognized as limiting the capacity of a machine oi this class to transmit power continuously.

It is with the above facts in view that I have devised the present mechanism which has i'orits general object the provision of an improved hydraulic power transmitting mechanism of high efliciency.

A more specific object is to provide a device so constructed that the rotating parts are in direct contact with the atmosphere, thus greatly facilitating the dissipation of any heat that is generated.

Another object is the provision of liquid recovering, replenishing and circulatory means which not only makes for economy of operation, but utilizes the air currents set up by the rotating parts to cool the liquid used in this system.

A further object is to provide an improved means 01 supporting thevariable stroke crank element.

A still further object is to provide a device with an improved arrangement of parts, which permits each cylinder to be separately demounted and which permits the assembly of all the parts with a minimum of time and eiiort.

Other objects and novel features of this invention will be pointed out and clearly defined in the claims at the close of this specification.

In the drawings:

Fig. 1 is a top plan view of a complete hydraulic transmission mechanism constructed in accord ance with my invention.

Fig. 215 a central vertical longitudinal sectional view.

Fig, 3 is a vertical cross-sectional view through the pump unit, the view being taken along the line 3--3 of Fig. 2.

Fig. 4 is a similar view taken through the stationary intermediate member located between the pump and motor units, on the line 44 of Fig. 2.

Fig. 5 is a vertical section taken on the line 5-5 of Fig. 2, illustrating part of the slidable pump stroke varying member in detail,

Fig. 6 is a detail cross-section on the line 6-4; of Fig. 2, showing the mounting for one end of the variable stroke crank element of the pump.

Fig. '7 is a cross-section on the line of Fig. 2.

Fig. 8 is a Fig. 5.

Fig. 9 is a vertical section, partly schematically arranged, showing an improved and alternative form of fluid collection, replenishment and circulatory system.

Fig. 10 is a. detailed view of a valve device.

Fig, 11 is a top plan view of guide means for the valve like that shown in Fig. 10.

vertical section on the line 88 of Before explaining the present invention, it isto be understood that the invention is not limited in its application to the details of construction and arrangement of parts described herein and illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced and carried out in various ways. It is also to be understood that the phraseology or terminology used herein is for the purpose oi description and not for limitation, and it is not intended to limit the invention beyond the terms of the several claims hereto appended as considered in view of the prior art and the requirements thereof.

Referring more particularly to the drawings, I have shown the device as comprising, broadly, a pump unit A, a motor unit B indirectly driven thereby, and an interposed stationary member 0 provided with means for establishing and controlling communication between the pump' and motor units.

The machine is carried by a stationary frame including a member Ill from which extend preferably diverging arms Ii secured to a transverse end plate i 2 outwardly of which is located a casing member I! secured thereto and cooperating therewith to define a sump ll. Secured against one face of the member I II and located between the arms II is a member is formed centrally'with a cylindrical or trunnion-like member ll. Secured to the opposite side of the mem-- ber II is a similar member i1 formed centrally with a trunnion-like member l8 and which constitutes the support for the motor unit B,

The pump unit 'A is carried by the members l2 and i5 and comprises a hollow rotor I! of cylindrical shape'h'aving a hub portion surrounding the trunnion member l8 and located within an outstanding flange 2i forming part of the member i5, roller bearings 22 of any suitable type being located betw the hub and the flange.

The opposite end of the rotor i9 is received within a recess 22 in the face of the end plate I2, this recess being defined between a flange 24 and a cylindrical bearing .hub 25. An appropriate roller bearing structure 25 is interposed between this end of the rotor and the hub 25. By this mounting, the rotor is adequately sustained by the stationary parts for rotation with respect thereto.

The rotor assembly further includes a series of I radial cylinders 21 which are closed at their outer ends except for ports 22 and which have their inner ends fitting into openings 29 in the rotor l5. These cylinders are preferably individually removable and are consequently represented as having attaching base portions 30 secured on the periphery of the rotor I! as by cap screws 5L,

Removably secured to the sides of the cylinders at the ports 28 therein arehollow arms 32 which constitute conduits and which have their other ends secured to the hub 20 at ports 33 therein, suitable packing being used at these joints to make them fluid tight. These hollow arms, like the cylinders, have attaching portions 35 secured to the hub as by cap screws 25. Any desired number of cylinders, together with the corresponding arms 32, may be provided. In the preferred form I have shown the pump A as having seven cylinders.

Slidable within the cylinders 21 are pistons 25 connected by wrist pins 3'! to connecting rods 22 which have their inner ends enlarged to form shoes or base portions 28. These shoes 39 are disposed against the outer periphery of a ring ill to which they are held by imeans of a pair of rings ll located at opposite sides of the series of connecting rods and fitting within grooves 42 in the shoes 39. The shoes 35 may slide circumferentially with respect to the ring 45 for automatically accommodating themselves to the various conditions brought about by movement of the stroke varying means to be described.

The means for driving the pump A comprises a drive shaft 42 passing through a stufilng box 44 located in a pocket 45 in the casing I3. Adjacent to the inner end of this shaft is a disk (I preferably formed integrally with the shaft 43 and which is secured to the rotor I! at the face of the hub 25 thereof, as shown at 48. The inner bly rotates.

Themeans for controlling the reciprocation of broadly described as a crank pin mounted so that it may be moved transversely of the machine to determine the axis about which the piston assem- This mechanism comprises a hollow laterally movable crank pin 56 supported on its front end by a relatively large. and rugged platelike member or slide 55 and supported on its inner end upon the drive shaft 45 by intermediate -means later to be described. The position of this mechanism determines the length end direction of the stroke of the pistons 56. The crank pin 55 and the upper central portion of the slide 55 are formed with aligned horizontally elongated 4 slots 15 through which the drive shaft 43 passes.

These slots I5 are of such size and shape as to permit the maximum desired lateral movement of the crank pin 55 and the slide 55 without bringing the inner peripheries of said slots into contact with the drive shaft 45.

The sleeve 56 terminates on one end in a. somewhat disk-like vertically elongated portion 51 having spaced overhanging flanges 58 at the top and bottom and located adjacent the disk 41. Each flange 58 is fitted with a guide 66, pinned as at 51 in the longitudinal slots 61a. Since theopposing faces of the flanges 5B and the guides are similarly curved, these parts may rock slightly with respect to one another to permit a slight adjustment between the parts. The guides 65, which may be made of bronze or any other suitable material, are slidably mounted on a relatively stationary plate 65 which is supported by a roller bearing assembly 88 mounted on the drive shaft 43.

Adjacent the disk-like portion 51 the crank pin 55' carries a roller bearing structure 59 located within the confines of and engaging the ring 40 which carries the connecting rods for the pistons 36. This roller bearing assembly is held in place by hub 65.

The front end of the crank pin 56 is supported by the hub Bil formed on the slide 55 and keyed as at ii. The inner end of the hub 60 is preferably tapered toward the axis so as not to interfere with a retaining ring 64 which is carried by the member I! and which holds the above described roller bearing assembly 26 in place.

end plate l2 and is provided wit downward extensions 69 terminating at their laterally arranged lugs or feet I0 slidably fitting within elongated slots II in the end plate i2, these slots being covered by plates 12. The

The slide 55 is movably mourgq; against the downward extensions 69 are preferably widely,

spaced so as to resist any tendency to be angularly displaced. The slide 55 is held in place againsthe, end plate l2 by the angled retaining members 13, secured as at 14 to the end plate l2 and overlying the outer faces of the extensions 59. .The lugs 10, the slots II and the members 13 cooperate to permit the slide 55 to be easily moved laterally of the machine but to hold said slide firmly in position as regards any other displacement. Suitable stopping means for any sort may be employed to limit the lateral motion of the slide 55 and of the parts moved by it. a

It will be seen that I have provided a laterally slidably crank mechanism firmly supported on both its ends, said support coming at either side of the center of pressure of the pump piston assembly. It will also be noted that the support afforded by the assembly cooperating with the disk-like wer ends in I portion 51 and by the feet or lugs-18 of the slide 55 form a final supporting means of triangular rela tion to each other, giving in effect a final three point suspension.

'The motor unit B includes a hollow rotor member 82 having a hub portion 88 rotatable about the trunnion-like member I8 and located within an over-hanging flange 84 on the member I1, a roller bearing structure 85 being interposed between the hub and the flange. A retaining plate 88 for the roller bearing is mounted on the end of the flange. The inner periphery of the plate 88 is hollowed out to contain a felt washer to prevent leakage of any oil which may get past the bearing 85. The other or outer end of the rotor 82 is closed by a plate 81 secured thereto, this plate carrying a stub shaft 88 which constitutes the driven shaft of the machine. As it is necessary to support the rotor 82 at a plurality of points, I have shown its intermediate portion as containing a roller bearing assembly 88 engaging upon a reduced step 88 on the trunnion like member I8. The bearing assembly 88 is held in place by the retaining ring 81 cooperating with the rotor 82. Beyond this step 88 the trunnion member is reduced to form an eccentric spindle 8| upon the preferably tapered end 82 of which is secured, as by a nut 88, an eccentric collar 84 upon which is mounted a ball bearing assembly 85 engaging against and supporting the outer 'end of the rotor 82. The eccentric collar 84 has a flange 88 at its inner end which cooperates with the plate 81 to retain the ball bearing assembly in place. a

The motor unit further includes a plurality of cylinders 88 having their outer ends closed except for ports I82 and having their inner ends fitting within openings 88 in the periphery of the rotor 88. As these cylinders are, like the pump cylinders, intended to be individually detachable, they are shown as having attaching portions I88 secured to the outer periphery of the rotor by the cap screws I8I. Detachably mounted on the sides of the cylinders 88 at the ports I82 therein are curved hollow arms I88 constituting conduits, and these arms are secured to the hub portion 88 at ports I84 therein. The arms have attaching portions I85 secured as by cap screws I88.

Slidable within the cylinders 88 are pistons I81 carried by connecting rods I88 which have their inner ends provided with'shoes I88 slidably bearing upon a ring II8 and held in place by a pair of retaining rings III at opposite sides of the piston rods and seated within grooves II2 in the shoes. bearing structure II8 engaged about the spindle 8I. This roller bearing assembly is prevented from displacement in one direction by the ring 81 and in the other direction by a ring I I4 engaged by screws II5 threaded through the collar 84 and accessible for adjustment upon removal of the plate 81.

In order that there may be proper timed communication between the pump A and the motor B, the trunnion member I8 is formed with a pair of ports H8 and H1 separated by a transverse partition II8, these ports being adapted to register with the ports 88 in the hub 28 ofthe pump rotor I 8. Similarly the trunnion member I8 is formed with ports H8 and I28 separated by a corresponding partition member and adapted to register with the ports I84 in the hub 88 of the motor rotor 82. Formed through the central member I8 and through the trunnion members Within the ring 8' is a roller,-

I8 and I8 are aligned longitudinally extending passages I2I and I22, the former communicating at their ends with the ports II 8 and H8 and the latter communicating at their ends with the ports H1 and I28. The members I8 and I8 with their passages and ports constitute and will be claimed as valves. The portion of the central stationary member I8 containing the passages I2I and I22 is supported by the webs I88 (see Fig. 4) of elliptical cross section and by the smaller webs I18 and I18, thus forming inter communicating chambers I15. It will be noted the webs I18 and I18 are substantially in line with the passages I2I and I22 respectively, allowing other fluid connections to be made with these passages as will be later explained.

The operation of the hereinbefore described parts is as follows:

The drive shaft 48 is connected to any suitable source of power and in this embodiment is supposed to be rotating in clockwise direction. As the drive shaft 48 is rotated, it carries with it the plate 41 which in turn rotates thepump rotor I8 andthe cylinders 21 and the arms 82 which are part of the pump rotor assembly. 0bviously, during each revolution of the rotor, the ports 88 at one time will be in communication with the port H8 and at another time with the port II1 of the member l8. As the cylinders '21 rotate they carry with them the pistons 88 and the connecting rods 88. On the exhaust stroke the shoes 88 will be held in.place against the ring 48 by the pressure exerted upon them by the fluid in the cylinders 21 through the pistons and connecting rods and on the suction stroke, the shoes 88 will be held in place by a similar but lower pressure, or, if such pressure be insuflicient, by the rings 4|. The ring 48 will also rotate on the bearing assembly 58. The only movement of the shoes 88on the ring 48 will be the small amount of sliding necessary to compensate for the varying angularities of the connecting rods at the various points in its path of travel.

If the crank pin 88 is in its middle position or so that its center coincides with the axis of the rotor I8, the cylinders 21 and the pistons 88 will obviously be rotating about a common center and there will be no reciprocation of the pistons.

The pump A is then in its zero or no stroke position and no fluid'will be pumped by it.

If the slide 55 be shifted to e left as viewed in Fig. 5, it will carry with it e crank pin 58. The center of rotation of the pis one 88 will no longer coincide with the axis of the rotor I8 but will be to the left of it, so that the pistons 88 will be reciprocated in the cylinders 21 and will perform one complete intake stroke and one complete exhaust stroke for each revolution of the rotor I8. The length of the stroke will depend upon the distance of the slide 55 and the crank pin 58 has been shifted. In the present embodiment, with the crank pin shifted to the left, the pistons 88 will be on their inward or suction strokes in all of the cylinders 21 whose corresponding hollow arms 82 have their ports 88 in communication with the port II8. Fluid will, therefore, be sucked up through the port II8, through the ports 88, the ports'28 and into the cylinders 21. At the same time the other pistons 88 will be on their outward or exhaust stroke in all cylinders whose corresponding ports 88 are in communication with the port I", so that fluid under pressure will be forced out of the cylinders 21, through ports 28. the arms 82 pump A. Pressure fluid entering the port I20.

will enter all the ports I04 that are then in communication with it and will travel through the corresponding arms I08 andtheports I02 into the outer ends of the cylinders 98. Pressure will thus be exerted upon the pistons I01, the connecting rods I08, the ring IIO, the bearings H3 and will react against the spindle 9|. As this spindle is positioned eccentrically to the axis of the rotor 82, the rotor will be caused to turn in a clockwise direction and the driven shaft 88 will thus be operated. As the stroke of the motor pistons I01 is fixed, the speed of the rotor 82 will depend upon the quantity of oil supplied by the pump A and as this may be varied from zero to maximum, the speed of the rotor 82 may similarly be varied. At the same time, the pistons I01 will be on their outward or exhaust stroke in all the cylinders 98 whose corresponding ports I04 are in communication with the port II9, so that fluid in these cylinders will be expelled, passing through the passages HI and being returned to the'port I I6 where it will again be sucked up by the cylinders 21 and then recirculated through this channel on the 'downward stroke of the pistons.

. If the slide 55 be moved through the zero position and to the right as looked at in Fig. 5, it will move with it thecrank pin 55 so that the center of rotation of thepump piston assembly will be to the right of the axis of the rotor I9. The entire operation of the pump A will then be reversed, pressure fluid being forced into the port IIG, through the passages I2I, into the port II9, where it will enter the ports I04 in communication with it and will cause the rotor 82 to rotate in a counter clockwise direction. The direction of rotation and the speed of the rotor 82, therefore, depend entirely upon the position of the crank pin 56. p 7

Any suitable means may be employed for shifting the slide 55'and hence of moving the above described crank pin mechanism, as for example, a screw and nut device of well known design. As

illustrated herein I have shown hydraulic power means for accomplishing this result, and have provided at each side of the machine and suitably secured to the end platl2 cylinders 15 closed at their outer ends and containing pistons 11 connected to plates 18 secured at 19 to the slide 55.- Fluid pressure conducting pipes 80 enter the outer ends of these cylinders. Fluid under pressure for operating these-cylinders 16 may be secured from any preferred source, as from a separate pump,

and controlled by any suitable valve control device. I prefer, however, to obtain pressure fluid from the main or working circuit of the transmission device and this is accomplished through not be described'here in detail, but contains,

among others, valves for continuously furnishing pressure fluid to an adjusting vavleby which the admission of pressure fluid to either of the cylinders 18 may be controlled. For controlling the h accomplished.

adjusting valve I have shown a floating lever device comprising a link II (see Fig. 1) attached on one end to the stem of the adjusting valve and on its other end movably attached to the lever I52. The other end of lever I52 is movably, connected to the rod 8 I which in turn is rigidly fastened to theslide 55, projecting through a passage in the casing I3. Means for operating the floating lever device is indicated'at I53 in Fig. 1. In operation of this control, an impulse applied to the lever I52 by means of the element I53 will cause the rod I5I to be pushed in or pulled out as the case may be. In one instance ,7

the adjusting valve will be so moved as to permit pressure fluid to pass through oneof the pipes 80 into one of the cylinders where it will react against the piston 11 and shift the slide 55 and occur as it is a physical impossibility to have the working parts fit so snugly as to entirely prevent it. Consequently, I have provided for collecting and returning such leakage, and, for convenience, I shall use the term leakage circuit to broadly designate the mechanism through which this is One embodimentof such a leakage circuit is shown in Figs. 1, 2, 4 and 5. I provide cooling tanks I29 and I3I which are connected for free intercommunication by the pipe I32 and which are secured to the stationary parts of the machine in any suitable manner. These tanks are preferably located at a point relatively low with respect to the pump A and the motor B so as to facilitate the collection of leakage as will be later described. They are also preferably placed near the outer ends of the rotating pump cylinders 21 They may be of any desired and practical size and shape, but I prefer 'to make them large enough to contain substantially more fluid than the leakage fluid collected therein, so that there will be a reserve supply at all times for replenishing the main fluid system and also so that fluid may be temporarily halted therein, thus allowing it to be cooled by the air currents stirred up by the rotating cylinders 21. As shown these tanks are of somewhat curved cross section, enabling a greater area to be positioned close to the path of i the rotating cylinders. They may be made of any suitable material, but are preferably made of aluminum or thin copper, because of the heat conducting properties of these metals and to re duce weight. Radiating fins may be added if desired.

For collecting the leakage from the motor B, I provide the member I8 with a passage I23 leading to a longitudinal passage I24 which extends into 7 the member I0 to abut its middle point. This passage I24 connects with a transverse passage I25 whose open end terminates in an outlet opening I25 between the webs I18 and I19. .Fluid discharged into the horizontal space [between webs I18 and I19 isfree to pass into the intercommunicating chambers 115 in the member I0. When fluid accumulating in the chambers I15 reaches the level of the overflow duct I21 it will pass through this duct into the pipe I29 and' then into the pipe I32 which is connected with tanks I29 and I3I. The overflow duct I21 may be located at any desired point below the passage I25, but I prefer to place it at about the level of the upper surface of web I19 so that considerable fluid may accumulate in the chambers I15, absorbing and carrying away heat from the member I0. The level of the fluid in the rotor casing 82 is determined by the position of the passage I23.

Fluid leaking from around the members I6 and I9 on their ends nearest the member III will pass through the aligned passages I33 in the members I5, Ill and I1 andwill drain through a vertical passage I34 into a vertical pipe I35 connected with the horizontal pipe I32 from whence it is free to flow into either of the tanks I29 and I3I.

Fluid leaking from around the valve member I6 at its end nearest the pump cylinders 21 will leak through passages (not shown) in the plate 41 and into the rotor casing I9. Fluid leaking from the inner ends of the pump cylinders 21 will find its way around the crank pin mechanisin and into the rotor casing I9. Fluid thus accumulated in the rotor casing I9 will overflow through the open spider 5I into the space I4 at the bottom of the casing I3 from which it passes through a passage I30 into thetank I29.

It will be observed that all of the fluid leaking from the various parts of the main or working circulatory system is eventually accumulated in the cooling tanks I29 and I3I.

Positive means for returning this leakage is provided and comprises a pump I31 driven from the drive shaft 43 by some suitable means such as a chain I39 trained about a sprocket I39 on the shaft of the pump I31 and about a sprocket I49 mounted on the drive shaft 43. This pump maybe of any preferred type and is here illustrated as a gear pump of a well known type and is made of a capacity large enough to supply at all times an excess of fluid over and above the amount needed to replenish the leakage in the main or working circulatory system. The suction side of the pump I31 is connected through a pipe I36 with the tank I3I. The pressure or discharge side of the pump I31 is connected to a pipe I4I through which fluid under pressure is conveyed to the valve block I42. As herein-v before noted, this valve block may be the same as that shown in the patent to Manly, No. 1,206,- 453. It contains valve mechanism through which fluid delivered to it by the pump I31 is admitted to the main circulatory system to make up for the fluid which has leaked out and maintain the volume of fluid therein substantially constant. The pipes I43 and I44 connect the valve distributing mechanism in the valve block with the passages I45 and I46 respectively in the member III, the latter passages passing through the webs I18 and I19 and communicating with the passages I2I and I22 respectively of the main circulatory system. The replenishing fluid will be fed alternatively into passages I2I or passages I22, that is into whichever pair of these passages at the time serving as the low pressure or return passages of the main circulatory system. The setting of the spring on the blow-oi! or exhaust valve I16 in the valve block determines the pressure built up by the pump I31 and hence the minimum pressure maintained in the low pressure passages of the main circulatory systern in practice it hasbeen found that the best results are obtained when this pressure is kept at higher than atmospheric pressure, the exact amount varying with individual installations and conditions.

The excess fluid delivered to the valve block I42 by the pump I31 and not requiredfor replenishing the main circuit or other purposes will be discharged through the blow 01! valve v I16 through the passage I11 in the member III and will enter one of the intercommunicating chambers I15 whence it will return to the tanks I29 and I3I in the manner hereinbefore described.

Another and improved embodiment of my leak-.- age circuit is shown in Figs. 9, 10 and 11. It embodies in novel manner the preferred features of a positive pressure replenishing system, broadly similar to that previously described, and of a gravity replenishing system whereby replenishment is accomplished through inwardly opening check valves acting under suction from within the main circulatory system and from the weight of the column of fluid in an elevated reserve tank.

The pump I31 and the method of driving it are the same as hereinbefore described. The pressure or delivery side of this pump is con- .nected to the pipe 24I.- Located on the top face of and suitably secured to a modified form of the .member III is a member 242 in which are formed a pressure chamber 243 and a reservoir 244, closed at their tops by the cover 245 in such a manner as to form fluid tight joints with the walls of the pressure chamber and of the reservoir. Fluid under pressure delivered by the pump I31 passes through the pipe I and enters the pressure chamber 243 through the port 246 which is preferably placed nearthe top of one of the walls of the pressurechamber so as to prevent fluid draining out of the chamber when the pump I31 is stopped. Located in the bottom of the chamber 243 are two check valves 246 and 241.

Valve 246 is connected with the passage 248 in the modified form of the member III, this passage intersecting and connecting the pair of passages I22 of the main circulatory system. Similarly valve 241 is connected with the pair of passages I2I through the passage 249. The check valve 246 is designed to open and admit fluid from the pressure chamber whenever the pressure in the chamber 243 exceeds that in the passage 248 and hence in the passages I22, but when the pressure in the passage 248 exceeds that in the chamber 243 the valve 246 will close and prevent any fluid passing into the chamber 243. Valve 241 operates in the same manner.

Controlling the pressure in the chamber 243 is an exhaust or blow-01f valve 259 located in the wall of the chamber adjacent the reservoir 244. This valveis preferably placed near the top of the chamber 243 so that any air that enters may rise and be quickly expelled. As shown, the valve'250 is of the piston type and is held on its seat by a spring 25I mounted on a suitable support as 252. The spring 25I may be made adjustable or may be set for any desiredpressure. When the pump I31 is in operation the force placed on the valve 259 by the spring 25I determines the pressure maintained in the pipe 2 and the chamber 243 and hence .the minimum pressure in passages 246 and 249 and the passages I2I and I22 of the main circulatory system. Pressure fluid will, therefore,

replaceleakage in the main circulatory system replenishing fluid may be supplied simultaneousany deficiency of fluid in the main circulatory system will be quickly made up. when the pump A is given stroke the pressure generated by it will exceed that in the chamber 243, under ordinary conditions, and the check valve 246' or 241.

' one or both of the valves'246 and 241 will open under the weight of the fluid in the pressure chamber 243 and replenishing fluid will be admitted into the main circulatory system. This A device, therefore, operates as a positive pressure leakage replenishing mechanism when the pumps A and I61 are in operation and as a gravity replenishing mechanism when the machine stands idle.

Excess fluid not needed to replace leakage will be discharged through the valve 250 into the cylinders 21 so that it may be cooled by the, air

reservoir 244. Located near the opposite end of the reservoir is. an overflow wall 253 which may be of any desired height but should be low enough to permit the easy flow of fluid between its top and the cover 245. Located between the walls 253 and 255 is a compartment 254 which is con-- nected with a passage 256 in the modified form of the member III. This passage 255 leads into i a cooling tank 251, hereshown as secured to the flower face of the member II). This tank is preferably placed low enough to facilitate the collection of leakage and adjacent the rotating pump currents generated by them. Positioned below the passage 256 in the tank 251 is a curved baflle plate 256 which retards the speed of fluid entering the tank through the passage 255 and thus prevents turbulence. An air vent 256 is located near the top of one wall of the tank 251. A.

strainer 26I is placed in the tank at an angular position, one of its ends being supported by the baiiie plate 256 and the other end restingin the opposite bottom corner of the tank 251. The

angular position of the strainer makes it pbssible to have incoming fluid enter the tank above the strainer while maintaining agood;head of fluid above the port 252, and also allows the fluid to pass through the strainer slowly and gradually. thus eliminating both dirt and air from the fluid.

- Connected to the port 262 is the pipe. 266 which leads to the suction or intake Leakage will be collected in the manner already described, such leakage being conducted side of the pump into the tank 251 through suitable connections,

one of which is indicated at 266 which is a port in the wall of the tank 251 connected to a pipe. not shown, connected in turn with the space I4 in the casing I3.

The circulation of the fluid will be clear from theforegoing description. Thespeed of the fluid dischargedthrough the valve 259 will be checked by the valve support 252 and by the fluid already in the reservoir. If any air has become mixed with the fluid, de-aeration will begin to take place in the reservoir andwill continue as the film of 1y to both of the pairs of passages I2I and I22 and In some instances it is desirable to maintain one or both rotor. casings completely filled with fluid as this retards leakage, particularly when the machine stands idleyand assures proper lubrication 01 all parts at starting. A serious objection to this in other devices of this class has been that the rotating parts churned the fluid and generated considerable heat. As the rotor casings in my device revolve with the other rotating parts, the fluid in them is held against them by centrifugal force and revolves with the rotor and with the other rotating parts. The only churning eflect, therefore, is the small amount caused by the reciprocation of the pistons and connecting -rods and in actual practice this has been found to be negligible. In my improved leakage Another vertical passage 261 leads from the bottom of the chamber 266 and is connected with the longitudinal passage I24, Figs. 2 and 9, which passes through the member I6 and the member I6 and connects with the passage I26; one end of which is open to the interior of the rotor casing 62. Fluid in the reservoir 24 will flow through the passage 265, into the the passage 261, the passages I24 and I22 and into the rotor casing 62, completely filling all of them. Leakage occurring from theinner ends.

of the cylinders 96 and from the end of the valve member I6 nearest them will cause a slight pressure in the rotor casing, causing the excess fluid to rise through the various communicating passages into the reservoir 244 and from there it will return to the tank 251 in the manner already described. v

' Eithr or both of the pump and motor units disclosed herein will function as either a pump or motor, with a variable or flxed stroke as desired, and either unit may be used in connection with two or more of the other units, suitable changes for this purpose being made in the intercommunicating means.

This application is a division of my copending application Serial No. 550,198, filed July 11, 1931, which is in part a continuation of my prior application, Serial No; 368,106, filed June 5, 1929.

I claim:

1. In a variable-stroke pump or motor havin a cylinder-carrying rotor, containing at central cavity, pistons in the cylinders of said rotor'hav- Ingconnecting rods extending into said cavity, a rotatable shaft extending into said cavity and having a direct connection with said rotor and a laterally movable crank element surrounding said shaft and operatively connected with .said connecting rods, the combination of a direct con-'- nection between said shaft and the'rotor, and a support for the crank element positioned between said direct connection and ,said connecting rods and permitting sliding movement-of the crank element, said support comprising a bearing member having its inner race carried by said shaft and-having'its outer race provided with a plate slidably fitted within guiding flanges on said crank element.

her 256, l

In a variable-stroke pump or motor, a rotary fluid flows'jdown the wall 253 and the passage 256. in axial alignment therewith, a cylindrical valve element entering said valve chamber and conveying fluid to and from said pump or motor, a revoluble shaft having one end rotatably supported upon said valve element and having a direct operative connection with said rotary cylinder element, a crank element surrounding said shaft and operatively connected with the pistons of the cylinders of said rotarycylindrical element, and means for supporting each end of said crank pin element comprising a slide positioned externally with respect to said rotary cylinder element and a second slide engaging a slideway rotatably supported upon said shaft 3. In a. variable-capacity pump or motor, a cylinder-carrying element and pistons in the cylinders thereof, a stationary, central, cylindrical valve member for conveying fluid to and from said pump or motor, a rotary valve chamber carried by said cylinder-carrying member and rotatable about said valve member, fluid connections between said valve chamber and said cylinders, stroke-changing mechanism comprising a laterally-movable crank pin operably connected with said pistons, a rotatable shaft extending through the laterally-movable crank element and directly connected with said rotor,.and multiple supporting means for said crank element positioned at both sides of the plane of said cylinders, one of said supporting means comprising a member slidably engaging said crank element and rotatably supported upon said rotatable shaft.

4. In a variable-capacity pump or motor, a cylinder-carrying rotor having a central cavity, pistons in the cylinders of said rotor having connecting rods extending into said cavity, a stationary, central, cylindrical valve member, for conveying fluid to and from said pump or motor, a rotary valve chamber carried by said cylindercarrying rotor and rotatable about said valve member, fluid connections between said valve chamber and said cylinders, a rotatable shaft extending into said cavity and having a direct connection with said rotor, a laterally-movable crank element surrounding said shaft and operatively connected with said connecting rods, a direct connection between said shaft and the rotor, and a separate support for each end of the crank element, one of said supports being positioned between said direct connection and said connecting rods and permitting sliding movement of the crank element. 1

5. In a rotary pump or motor, a rotary element having a plurality of cylinders circumferentially spaced to form a centralspace, said rotary element also having a part forming a rotary valve chamber in axial alignment with said central space, means for rotatably supporting said rotary element, a rotatable shaft extending into said central space and connected .to said rotary element, pistons in said cylinders, a variable-throw crank mechanism extending into said central space and operatively connected with said pistons, one end of the said crank mechanism being adjustably supported upon the support for said rotary element and the other end thereof being adjustably supported upon said rotatable shaft, means for adjusting the throw of said variable-throw crank mechanism, t tionary cylindrical valve extending into said valve chamber for conveying fluid to and from said pump or motor, and fluid connections between said valve chamber and said cylinders, said rotary element rotating in substantially free air during operation of the pump or motor,

6. In a rotary pump or motor, a pair of stationary supporting members, a hollow rotary cylinder and valve-chamber element extending between said stationary supporting members and having its ends rotatabiy supported thereon, a rotatable shaft extending through one of said stationary members and projecting into said rotary element, said shaft being directly connected to said rotary element, a plurality of cylinders formed in said rotary element, pistons in said cylinders, a variable-throw crank mechanism operatively connected with said pistons and extending into said rotary element, one end of said crank mechanism being adiustably supported upon one of said stationary members and the other end of said crank mechanism being adjustably supported upon said rotatable shaft,

means for adjusting the throw of said variablethrow crank mechanism, a rotary valve chamber formed in said rotary element and in axial alignment therewith, a stationary cylindrical valve entering said valve chamber for conveying fluid to and from said pump or motor, and fluid connections between said rotary valve chamber and said cylinders, said rotary cylinder and valve chamber element rotating in substantially free air and forming an enclosing casing for all parts of said pump or motor. intermediate said stationary members.

7. In a variable-capacity pump or (motor having a cylinder-carrying element and pistons in the cylinders thereof, a stroke-changing mechanism comprising a laterally movable crankelement operatively connected with said pistons, a rotatable shaft extending through the laterally; movable crank element and directly connected with said cylinder-carrying element, and multiple-supporting means for said crank element positioned on both sides of the plane of said cylinders, one of said supporting means comprising a slide rotatably supported upon said shaft and slidably engaging said crank element, said slide permitting movement of said crank element transverse the axis of said shaft to vary. the stroke of said pump or motor and being formed to permit limited rocking movement of said crank element along the axis of said shaft to permit adjustment of said crank element with respect to said multiple supporting means. "8. In a variable-stroke pump or motor havinga cylinder-carrying rotor and pistons in the cylinders' thereof, a central, cylindrical valve member for conveying fluid to and from said pump or motor, said rotor having a rotary valve .chamber, fluid connections between said valve chamber and said cylinders, a rotatable shaft directly slide extending on each side of said rotatable shaft.

9. In a variable-stroke pump or motor, a rotor having a central cavity open at one end and having a rotary valve chamber in axial alignment therewith, a cylindrical valve element in said valve chamber for controlling the flow of fluid ,to and from said pump or'motor, a rotatable shaft secured to said rotor adjacent the closed end of said cavity and projecting from the open end thereof, a transversely-slidable and non-rotatable crank element positioned in said cavity and surrounding said shaft, cylinders in said rotor, fluid connections between said valve chamber and said cylinders, a piston assembly comprising a piston in each of said cylinders and an operative connection between each piston and said crank element, and a separate support for each end of said crank element, said supports being positioned on opposite sides of the center of pressure of said piston assembly and permitting transverse sliding movement of said crank element to vary the stroke of said pump or motor.

HUGO A. CENTERVALL.

CERTIFICATE OF CORRECTION.

' P atent N0. 2,159,005. May 25, 1959.

HUGO A. CENTERVALL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correctionas follows: Pege2, second coluinn, line 67, for the word "for" read of; line T1, for "slidably reed siidable; page 1 first column, line 75, for vavle" read valve; some page, second column, line 67', for "abut" read about; and that the'said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

signed and sealed thislst da of August, A. D. 1939'.

Henry Van Arsdale, (SealY Acting Commissioner of Patents. 

